1. Field of the Invention
The invention relates to an apparatus for assembling a post-CMP cleaning brush; in particular, to an apparatus that can assemble the post-CMP cleaning brush more easily.
2. Description of the Related Art
As is well known, semiconductor devices are fabricated from semiconductor wafers, which are subjected to numerous processing operations. These operations include, for example, impurity implants, gate oxide generation, inter-metal oxide depositions, metallization depositions, photolithography pattering, etching operations, chemical mechanical polishing (CMP), etc. Although these processes are performed in ultra clean environments, the very nature of many of the process operations is to blame for the generation of surface particles and residue. For instance, when CMP operations are performed, a film of particles and/or metal contaminants are commonly left behind.
Because surface particles can detrimentally impact the performance of an integrated circuit device, wafer-cleaning operations have become a standard procedural requirement after certain process steps. Although cleaning operations are rather procedural, the equipment and chemicals implemented to perform the actual cleaning are highly specialized. This specialization is important because each wafer, being at different stages of fabrication, represents a significant investment in terms of raw materials, equipment fabrication time, and associated research and development.
To perform the cleaning operations in an automated manner, fabrication labs employ cleaning systems. The cleaning systems typically include one or more brush boxes in which wafers are scrubbed. As shown in FIG. 1a, each brush box includes a pair of brushes 10, such that each brush 10 scrubs a respective side of a wafer 1. To enhance the cleaning ability of such brush boxes, it is common practice to deliver cleaning fluids through the brush 10 (TTB). Referring to FIG. 1b, TTB fluid delivery is accomplished by implementing brush cores 11 that have a plurality of holes that allow fluids to be fed into the brush core 11 at a particular pressure to be released into an outer brush 12 surface. The outer brush 12 surface is made out of a very porous and soft material so that direct contact with the delicate surface of a wafer 1 does not cause scratches or other damage. Typically, the outer brush 12 surface is made out of polyvinyl alcohol (PVA) foam. Although, other materials such as nylon, mohair or a mandrel wrapped with a polishing pad material can be used. It is noted that the outer brush 12 is provided with a hollow portion 12a for the brush core 11 in passing through.
The outer brush 12 must be replaced after cleaning a predetermined number of wafers 1. The conventional method for assembling a new outer brush 12 and the brush core 11 is shown in FIG. 2a, FIG. 2b, FIG. 2c, and FIG. 2d. Firstly, two pads 20, shown in FIG. 2a and made of PVC, are passed through the hollow portion 12a of the outer brush 12 as shown in FIG. 2b. Then, the hollow portion 12a of the outer brush 12 is expanded by pulling the pads 20 while the brush core 11 is passed through the hollow portion 12a of the outer brush 12 as shown in FIG. 2c. Finally, the pads 20 are drawn out of the hollow portion 12a of the outer brush 12 to complete the assembly of the post-CMP cleaning brush 10.
The conventional assembly method has the following disadvantages:
1. Since it is difficult to actually expand the pads 20 into the hollow portion 12a of the outer brush 12, it is difficult to pass the brush core 11 through the hollow portion 12a of the outer brush 12.
2. Since it is difficult to smoothly pass the brush core 11 through the hollow portion 12a of the outer brush 12, the outer brush 12 is easily damaged when the brush core 11 passes through the hollow portion 12a of the outer brush 12.
3. Since the material of the pads 20 is the same as the outer brush 12, it is difficult to draw the pads 20 out of the hollow portion 12a of the outer brush 12. Thus, the pads 20 are easily damaged.
In order to address the disadvantages of the aforementioned assembly method for a post-CMP cleaning brush, the invention provides an apparatus that can assemble the post-CMP cleaning brush more easily.
Another purpose of this invention is to provide a method for assembling a post-CMP cleaning brush without damaging its outer brush.
Accordingly, the invention provides an apparatus for assembling a post-CMP cleaning brush having a brush core and an outer brush. The outer brush is provided with a hollow portion, and the apparatus comprises a base, a fixed member, a sliding member, a plurality of posts, and an actuating device.
The base holds the brush core and the outer brush, and the fixed member is disposed on the base. The sliding member is disposed on the base in a manner such that it is located at the opposite side of the fixed member relative to the outer brush disposed on the base. The posts, disposed on the sliding member, pass through the fixed member and the hollow portion of the outer brush so as to assist the brush core in passing through the hollow portion of the outer brush. The actuating device connects with the brush core so as to pass the brush core through the hollow portion of the outer brush and separate the posts, inserted into the outer brush, from the outer brush.
In a preferred embodiment, the apparatus further comprises a guiding member, connecting with the brush core, to make it easier to pass the brush core through the hollow portion of the outer brush.
Furthermore, the guiding member is provided with a plurality of grooves corresponding to the posts respectively. Thus, the guiding member slides along the posts by the grooves when the guiding member, connecting with the brush core, passes through the hollow portion of the outer brush.
Furthermore, the guiding member is provided with a catch rod, and the fixed member is provided with a first through hole for the catch rod passing through so as to prevent the brush core, inserted into the outer brush, from separating from the outer brush.
In another preferred embodiment, the fixed member is provided with a second through hole for the brush core passing through.
In another preferred embodiment, the fixed member is provided with a plurality of third through holes for the posts passing through.
In another preferred embodiment, the apparatus further comprises a hinge and a plate. The hinge is disposed on the sliding member. The plate connects with the hinge in a manner such that it rotates relative to the sliding member so that the posts separate from the outer brush when the actuating device separates from the brush core.
In another preferred embodiment, the actuating device comprises a connecting member, a cylinder, an air valve, and a pressure regulator valve. The connecting member connects with the brush core. The cylinder connects with the connecting member so as to push the brush core forward via the connecting member. The air valve communicates with the cylinder so as to actuate the cylinder. The pressure regulator valve communicates with the air valve.
In another preferred embodiment, the sliding member is provided with a plurality of first basic holes for disposal of the posts thereon.
In another preferred embodiment, the fixed member is provided with a plurality of second basic holes, and the sliding member is provided with a plurality of supports. The apparatus further comprises a plurality of link rods disposed on the base in a manner such that the link rods are inserted into the second basic holes and held by the supports of the sliding member.
In another preferred embodiment, the base is provided with a concave portion for disposal of the outer brush thereon.
In another preferred embodiment, this invention provides a method for assembling a post-CMP cleaning brush. The method comprises the following steps:
(a) providing the post-CMP cleaning brush having a brush core and an outer brush, wherein the outer brush is provided with a hollow portion;
(b) providing an assembly apparatus having a base, a fixed member, a sliding member, a plurality of posts, an actuating device, and a guiding member;
(c) disposing the outer brush on the base and inserting the posts into the hollow portion of the outer brush;
(d) moving the sliding member so as to pass the posts through the hollow portion of the outer brush;
(e) connecting the guiding member and the brush core;
(f) inserting one end, connecting with the guiding member, of the brush core into the sliding member while disposing the other end, connecting-with the actuating device, of the brush core on the base;
(g) passing the brush core through the hollow portion of the outer brush by the actuating device;
(h) separating the guiding member from the brush core, and passing the guiding member through the fixed member; and
(i) drawing the posts out of the hollow portion of the outer brush along with the sliding member by the actuating device so that the brush core is adjacent to the outer brush to complete the assembly of the post-CMP cleaning brush.
Furthermore, the posts are made of plastic steel.